Uroteuthis Duvaucelii Research Articles

Spatiotemporal distribution patterns of cephalopods and their responses to changes in the marine environment in the coastal waters of Zhejiang, China

IntroductionLike pelagic fishes, cephalopods represent fishery resources with high worldwide potential and an important evolutionary node animal group. Thus, exploring the spatial and seasonal variations in cephalopod distribution and their associations with environmental factors is important for elucidating cephalopod diversity and the distribution of cephalopods under changing environmental conditions and for developing reasonable resource management and conservation measures.MethodsOn the basis of trawl survey data from 123 stations in the coastal waters of Zhejiang, China, in the spring and autumn of 2021, the relationships among the cephalopod species composition and diversity characteristics and the spatial and seasonal changes and environmental factors were investigated via the relative importance index (IRI), the alpha diversity index, and the GAM.ResultsThe results revealed that the cephalopods in the coastal waters of Zhejiang belonged to three orders, six families, and 10 genera and that the dominant species were gradually replaced by species of minor economic importance and endemic small-scale fishery species. In spring, Uroteuthis duvaucelii was the dominant species, the resource density in the southern coastal waters of Zhejiang was relatively high, and the overall distribution increased from northeast to southwest. In autumn, U. duvaucelii and Abralia multihamata were the dominant species, and the coastal waters of Zhejiang presented two high-density distribution areas in the northern and central waters, with lower resource density in the southern waters. Analysis of the alpha diversity index revealed relatively low cephalopod community diversity, with significant differences in spatial and seasonal distributions. The GAM revealed that, in spring, surface dissolved oxygen and sea bottom temperature led to significant changes in cephalopod resource density (p<0.05), and water depth significantly affected cephalopod resource density (p<0.01); in autumn, only water depth significantly affected cephalopod resource density (p<0.01).DiscussionThe cephalopod resources in the coastal waters of Zhejiang are under the dual stresses of fishing and environmental changes. The protection and restoration of traditional economic cephalopod resources are needed to ensure their sustainable development and utilization.

Trace elements and the environmental factors influencing early life-growth of the squid, Uroteuthis duvaucelii

Trace elements and the environmental factors influencing early life-growth of the squid, Uroteuthis duvaucelii

Morphometrics and Growth Patterns of Squids in the North and South Coasts of Java, Indonesia

Highlight Research The mitre squid (Uroteuthis chinensis), the Indian squid (Uroteuthis duvaucelii), and the purpleback flying squid (Sthenoteuthis oualaniensis) were identified. Morphometric differences among three squid species were analyzed. Microanatomy observations on the shapes of the sucker rings were important for species identification. Hypoallometric and isometric growth patterns were observed. Abstract Squids play vital ecological and economic functions as keystone species in marine food webs and integral components of global capture fisheries. However, a comprehensive understanding of their diversity and life history characteristics in Indonesian waters is still poorly understood. This study aimed to identify squids that inhabited Java's northern and southern coasts and examine their growth pattern through morphometric analysis. Six hundred eighteen squid samples were collected fishers caught from May to September 2022 in Blanakan and Palabuhanratu Bay, representing two areas of interest. The body size and the shape of sucker rings of squids were observed using morphometric method. Kruskall-Wallis test, Principal Component Analysis, and Spearman's correlation were performed to investigate morphometric variation and relationships. The length-weight relationships were estimated for each species.. This study reported three species of squid on the north and south coasts of Java, namely the mitre squid (Uroteuthis chinensis), the Indian squid (Uroteuthis duvaucelii), and the purpleback flying squid (Sthenoteuthis oualaniensis). There were significant differences observed in ten morphometric variables among the three species of squid (p < 0.05), with fin width, fin length, and sucker ring teeth identified as the key distinguishing feature for the squids. Spearman's correlation indicated stronger associations between mantle and fin variables (ρ = 0.666-0.967, p < 0.05) than those between mantle and head variables (ρ = 0.380-0.864, p < 0.05).Mantle length-weight relationships revealed a hypoallometric growth pattern for U. chinensis and U. duvaucelii, while S. oualaniensis exhibited an isometric growth pattern. The finding of this study provides valuable insights concerning the growth of squids that reflect variation in ontogenic development, trophic ecology, and environmental conditions in Indonesian waters.

Latitudinal Difference in the Condition Factor of Two Loliginidae Squid (Beka Squid and Indian Squid) in China Seas

Cephalopod fisheries in the China Seas have witnessed an increasing trend in the catches of coastal cephalopods since the 1990s, with Loliginidae squid emerging as the main commercial target species. However, climate change and overfishing have led to a dramatic reduction in Loliginidae squid resources, highlighting the need to improve monitoring, protection, and management of this species. The Loligo beka and Uroteuthis duvaucelii are widely distributed along the coastal areas of the China Seas, and have commercial and ecological importance. Despite having overlapping distributions, similar life histories, and a strong dependence on the marine environment, there is limited knowledge about their growth and responses to environmental changes, hindering the effective management of their resources. In this study, we investigated the interspecies and intra-species differences in condition factor and their responses to temperature changes by analyzing data collected from wide coastal areas of the China Seas from June 2019 to November 2020. The findings showed that both species exhibited allometric growth and reproduced throughout the year, with two main breeding peaks. There were significant monthly variations and latitude differences in the intra-species growth, with a higher proportion of small-sized individuals (between 5 and 10 g for L. beka and between 10 and 20 g for U. duvaucelii) in low-latitude waters. The latitudinal differences in body weight and distribution between and within the two species were mainly due to natural habitats, especially temperature. Our mixed effect model results demonstrated that both species’ body weight increased with increasing temperature, suggesting that Loliginidae squid have significant environmental adaptability and can be used as an indicator species for studying environmental changes in the China Seas. These findings have significant implications for understanding the population dynamics, species development, and regionally specific management of Loliginidae squid fisheries in the China Seas.

Population dynamics of two squid species, <em>Uroteuthis duvaucelii</em> (D'Orbigny, 1835) and <em>U. singhalensis</em> (Ortmann, 1891) (Family: Loliginidae) in the Trincomalee bay, Sri Lanka

In the Trincomalee bay of Sri Lanka, two species of squids, Uroteuthis duvaucelii and U. singhalensis, support profitable small-scale fisheries. The present study is an attempt to assess the fisheries of these two squid species using length-based stock assessment methodologies. Length frequency data collected from the landings of two species, collected during the fishing season from May to October 2003 were analyzed using FiSAT II software package. The asymptotic length (mantle length) and growth constant of U. duvaucelii were 31.8 cm and 0.90 yr-1 respectively and of U. singhalensis were 31.2 cm and 0.72 yr-1 respectively. Using the mortality coefficient estimates based on these growth parameters, exploitation rates (E) of U. duvaucelii and U. singhalensis during the study period were found to be 0.55 and 0.44 respectively. Optimal fishing strategies determined by relative yield-per-recruit (Y’/R) analyses of two squad species indicated that the sizes of first capture (Lc) and E were at sub-optimal levels. As both squid species are exploited by the same fishing gear, optimal E values predicted by Y’/R analyses cannot be achieved. This analysis indicates that levels of exploitation during the study period having Lc of 15.8 cm for U. duvaucelii at E = 0.55 and 14.3 cm at E = 0.44 for U. singhalensis be maintained. It is therefore concluded that fishing effort and the sizes of the first capture of the two squid species in the Trincomalee bay do not require adjustments through fishery regulations for the sustainability of their fisheries.

Fish Catch Rate and Fish Composition of Commercially Operated by Multi-Day Trawling off Sindhudurg Coast of Maharashtra, India

The commercial-operated multi-day trawlers from Sindhudurg coast carried out fishing operations at Malvan landing center, South Konkan region, Maharashtra, India in the mean depth range of 18–31 m in September, 2016 to May, 2018 to assess the changing trends in the fish catch composition, catch and discards rate by multi-day trawlers operating along the Sindhudurg coast of Maharashtra state. The average catch rate was observed 25.03 kg h-1 and 31.72 kg h-1 with average discards 5.07 kg h-1 and 7.81 kg h-1 by multi-day trawler during 2016–17 and 2017–18 respectively. During two fishing seasons, the average catch rate was 28.37 kg h-1, with average discards of 6.44 kg h-1 by multi-day trawlers. Major catch composition of multiday trawlers comprised Arius maculatus, Parastromateus niger, Lactarius lactarius, Otolithes cuvieri, Lepturacanthus savala, Rastrelliger kanagurta, Scomberomorus guttatus, Cynoglossus macrostormus, Uroteuthis duvaucelii, and Penaeid prawns. Discards comprised juveniles of commercial species and adults of low market value fishes. Cod end mesh size of trawl net varied from 15–35 mm depending on the fishery resources harvested. Duration of fishing trips by multi-day trawlers varied from 2–4 days, peak fishing activities were observed during October to December followed by February in terms landing. The study clearly indicated an increase in the average catch rate h-1 trawler-1 during the year 2017–18 compared to the previous year 2016–17 along the Sindhudurg coast. The t-Test performed on fish catch and discard of multi-day trawlers showed a statistically significant difference (p<0.05) in a fish catch (kg h-1) and fish discards between two fishing seasons, i.e., 2016–17 and 2017–18.

Biomedical potential of β-chitosan from cuttlebone of cephalopods

Polymeric β-chitosan allomorph characterized by parallel arrangement of linear polysaccharide comprised of β-(1→4)-linked-D-glucosamine and N-acetyl-D-glucosamine was isolated and characterized from the gladius of Indian Ocean Squid (Uroteuthis duvaucelii) and spineless cuttlefish (Sepiella inermis). The β-chitosan from U. duvaucelii displayed considerably greater attenuation potential against hydroxymethylglutaryl coenzyme-A reductase, dipeptidyl peptidase-4, I converting enzyme, and 5-lipoxygenase (IC50 0.15-0.53mgmL-1) than those exhibited by α-chitosan of comparable molecular weight. Comparatively lesser conformational rigidity of β-chitin could result in its greater susceptibility to deacetylation (86-87%) contrasted to the α-allomorph (~83%), consequently delivering enhanced functionalities than those exhibited by α-chitosan. Porous β-chitosan scaffolds displayed an average pore size of lesser than 50μm, and its binding capacity was significantly higher than that exhibited by α-chitosan (p<0.05). Potential pharmacological activities reinforced by lesser binding affinities and intermolecular energy of β-chitosan with the target enzymes recognized its prospective biomedical applications.

Antioxidant activity of extract from some squid species in Khanh Hoa

The antioxidant activities against DPPH free radical of crude extracts using ethyl acetate and methanol from ink sac, muscles, and bones of 5 squid species (Uroteuthis chinensis, Uroteuthis sibogae, Uroteuthis duvaucelii, Sepia esculenta, Sepioteuthis lessoniana) collected in Khanh Hoa waters were investigated. These activities ranged from 4.21% (ethyl acetate extract from ink of U. chinensis) to 54.51% (methanol extract from muscle of S. esculenta.). The functional group analysis by infrared adsorption spectrum (FTIR) in these crude extracts revealed the absorption peaks of melanin in ink, polysaccharide in bone and protein in muscle extracts. In addition, the SDS-PAGE result of some methanol extracts showed the presence of proteins with a molecular weight of 30-150 kDa.

Species composition and spatio-temporal variation of bycatch from mid-water trawlers operating in the Arabian Sea along north-west coast of India

Abstract The mid-water multiday trawl fishery along the north-west coast of India generally targets adult largehead hairtail, Trichiurus lepturus. Bycatch landed by the commercial mid-water multiday trawlers operated from Veraval harbor during August 2017–December 2019 was investigated by analyzing catch composition with respect to its spatial and temporal patterns. A total of 834 bycatch sample observations from mid-water trawl fishery were examined. Bycatch comprises of 123 species and account for 53.36% of the total catch. Highest composition in bycatch comprises of teleosts (62.09%), cephalopods (35.88%), crustaceans (1.47%) and elasmobranchs (0.56%) respectively. Uroteuthis duvaucelii, Sepia elliptica, Nemipterus japonicus, Otolithes cuvieri, S. pharaonis, Priacanthus hamrur, Sepiella inermis and Saurida tumbil were the dominant species with high annual average catches; and together contributed 50.30% of total bycatch. Discards formed 6.32% of total catch and consisted of 62 species belonging to 29 families. The most common discards were juveniles of S. tumbil, N. japonicus, Platycephalus indicus, O. cuvieri, Johnius glaucus and T. lepturus. CPUE of bycatch differed significantly between the seasons with the lowest being in summer and highest in post-monsoon period. Minimum bycatch rates were observed in the offshore waters than inshore waters. Endangered, Threatened and Protected (ETP) species listed in CITES as well as IUCN were also observed. The present study revealed that quantities of bycatch landed off northwest coast of India in the Arabian Sea were relatively higher than that landed by mid-water trawlers operating in other parts of the world. Hence the mid-water trawl fishery operating in north-west coast of India and targeting largehead hairtail needs to be closely monitored to mitigate and reduce the quantity of bycatch landed by them.

Angiotensin-I Converting Enzyme Inhibitory Activities of Common Edible Cephalopods and their Antioxidative Effects using differentin vitroModels

Antioxidant and antihypertensive potential of ethyl acetate-methanol (EtOAc-MeOH) extract of cephalopods, Amphioctopus marginatus, Uroteuthis duvaucelii, Sepia pharaonis, Sepiella inermis and Cistopus indicus were evaluated using different in vitro systems. EtOAc-MeOH fractions of S. inermis, A. marinates and C. indicus showed greater ferrous ion chelating ability (IC90 5.01–5.8 mg/mL), and were effective in neutralizing the ABTS (IC90 3.5–4.01 mg/mL), and DPPH radicals (IC90 4.69–5.8 mg/mL). The utilities of deconvolated 1H and 13C-NMR spectroscopy for analyzing the signature peaks and abundance of bioactive functional groups in the extracts of cephalopods were illustrated. The EtOAc-MeOH extract derived from S. inermis showed greater angiotensin-converting enzyme-I (ACE-I) inhibitory activity (IC90 0.45 mg/mL) than other cephalopods (IC90 > 0.50 mg/mL). A significant colinearity was found between the electronegative groups present in the downfield position of NMR spectra vis-à-vis antioxidative and ACE-inhibitory activities of EtOAc-MeOH extracts from C. indicus and S. inermis. Practical Applications The edible cephalopod species are largely accessible in the coastal areas of India and exhibited a number of potential bioactivities against various diseases caused by free radical formation that can cause oxidative stress. This study revealed the bioactive potential of cephalopods, particularly Sepiella inermis, Amphioctopus marginatus and Cystopus indicus as potential angiotensin-converting enzyme inhibitors. The utilities of nuclear magnetic resonance-based spectroscopic tools for analyzing the relative abundance of the functional groups, which were responsible for bioactivities present in the ethyl acetate-methanol extracts of cephalopod species have been illustrated. The results from the present study will be helpful to develop new generation leads as nutraceuticals from the cephalopod species and in combating oxidative stress induced hypertensive disorders.